Roof, who is representing himself, will not be allowed to approach the jury, the witness stand or the bench during the proceedings, federal district court judge Richard Gergel said in the one-paragraph order.

The document, which was issued during a closed-door hearing on whether Roof was competent to represent himself and stand trial — Gergel ruled that he is — instead orders Roof to remain at a courtroom lectern during the proceedings.

Gergel did not cite a reason for the restrictions, and it's unclear if the judge will require similar rules for prosecutors — a point, said Richard Dunham, executive director of the non-profit Death Penalty Information Center, that could bias the jury against Roof and unfairly influence its decision to execute him.

“At this stage of the proceeding, he is still presumed innocent of death,” Dunham told NBC News. “Restrictions on defendants and their movements and anything that has the appearance of a security restriction can only be constitutional if they are supported by findings of fact that the restrictions are necessary for safety reasons.”

Dunham added that if the order was not for security, but was instead to maintain the court’s decorum, the rules should apply equally to prosecutors and the defense.

“They can’t advantage one side over the other,” he said.

A spokesperson for the United States Attorney's office in South Carolina declined to comment, as did a spokesperson for the court's administrative office in Washington, D.C.

Sarah Gannett, a lawyer on Roof's defense team, also declined to comment.

Chris Adams, a criminal defense lawyer in Charleston who has handled death penalty cases, said he expects Gergel to clarify the order on Wednesday so that it applies equally to prosecutors and Roof.

“It will be significant symbolically if the lawyers for the government and for Mr. Roof are treated differently,” he told NBC News. “That would certainly create a problem.”

But, Adams added: “Apparently the only person who doesn’t get that is Dylann Roof, because he hasn’t objected to the order.”

John Blume, a professor of trial techniques at Cornell University and director of the school's Death Penalty Project, said it’s possible the case was handled similarly during the initial phase of the trial, when Roof briefly represented himself.

“Maybe the order is no more than the judge trying to put down [the rules] so Roof can see what he’s supposed to do,” Blume told NBC News. “If they didn’t handle it that way, it’s strange.”

Sheri Lynn Johnson, a law professor who co-founded Cornell's Death Penalty Project in 1993, told NBC News that she’d never heard of such an order before — though she added it was very rare for a death penalty defendant to represent himself.

The closest case law, she said, forbids the shackling of such defendants during sentencing because of its "prejudicial effect," as Supreme Court Justice Stephen Breyer put it in a majority opinion on the subject in 2005.

In Roof’s case, Johnson said, requiring him to stand at a lectern could do the same thing.

“It will impair his ability to be persuasive to the jury,” she said. “Part of the drama of the trial is approaching the jury and making eye contact.”

Roof has said he plans to make an opening statement during his sentencing, though he does not intend to present evidence or call witnesses.

The government, meanwhile, plans to call 38 victims to the witness stand.

Still, Johnson said, Roof can always decide to handle his sentencing differently, and he can cross-examine witnesses if he chooses to.